Expansion-auger.



J. W. CALDWELL. EXPANSION AUGBB. APPLIOATION FILED JUNE 24, 190s.

Patented Jan. 4, 1910.

l I l I I l l l l I l l :u

'JOI-IN WILLIAM CALDWELL, 0F TORONTO, ONTARIO, CANADA.

EXPANSION-AUGER.

Specification of Letters Patent.

Patented Jan. 4, 1910.

Application filed June 24, 1908. Serial No. 440,180.

To all whom Lt may concern:

Be it known that I, JOI-IN WILLIAM CALD- WELL, a subject of the King of Great rBritain, and resident of the city of Toronto,

in the county of York, in the Province of Ontario, in the Dominion of Canada, have invented certain new and useful Improvements in Expansion-Angers, of which the following is a specification.

The invention relates to improvements in expansion angers as described in the following specification and illustrated in the accompanying drawings that form part of the same.

The invention consists essentially in the novel construction and arrangement of parts whereby adjustable cutters are arranged in tangential relation to the central lead screw and held in parallelly arranged grooves in the body portion.

The objects of the invention are to facilitate the digging of post holes, to devise an auger easily adjustable for the digging of holes of different sizes, to insure a good clearance in operation, and to provide a tool in which the parts may be easily removed and replaced.

In the drawings Figure l is a perspective view of one form of my invention, part of one of the cutting blades being broken away. Fig. 2 is a perspective view of a slightly modified form of my invention. Fig. 3 is an underside plan view of Fig. l. Fig. l is an underside plan view of Fig. 2. Fig. 5 is a sectional view through the line A B Fig. 3. Fig. 6 is a sectional elevation through the line C D Fig. 4. Fig. 7 is an enlarged sectional view through a portion of one of the spiral flanges and one of the reversible cutters, showing the double beveled back edge of the said cutters.

Like numerals of reference indicate corresponding parts in each figure.

Referring to the drawings l is the body of the auger formed of a pair of semi-circular spirally inclined flanges 2 forming part with the central hub portion 3, said inclined flanges having an arc-shaped flange I eX- tending upwardly from their outer edges and increasing in height toward the lower portion of the said spiral flanges.

5 are dove-tailed grooves or channels formed in the under face of the flanges 2 having the outer beveled edge 6 and the inner beveled edges 7.

7a are channels forming part with the channels 5 and sloping upwardly and outwardly from the top of the beveled edges 7 to the beveled edges 7 b. The lower edges of the spiral flanges 2 are cut away from the central portion of the body so that the upwardly and outwardly beveled edges 7 b form the terminal edge.

S are cutters, each formed with a front cutting edge 9 and a double beveled back edge 10, said cutting edge being adapted to fit under the beveled edge 7 and the beveled back edges l() to lit under the beveled edges 6. The top faces of the cutters 8 are cut away to form a beveled shoulderI 8a which abuts the beveled edges 7b so that the portion of the said cutters projecting beyond the center of the device at the lower side of the spiral flanges is rigidly supported and the upper surface of said cutters projecting beyond said edges 7b form a continuation of the upper spiral faces of the flanges terminating in the cutting edges.

12 are longitudinal slots in the cutters 8 having beveled edges and extending from a point adjacent to one end to about the center of said cutters through which a flat headed screw 13 is inserted, and countersunk therein.

14 are flanges extending upwardly from the outer edge of the cutters 8 and rising from the horizontal cutting edge to the height of the annular fianges t on the flanges 2. These outer flanges form critters for cutting away the earth at the sides as the cutters 8 cut into it, thus the auger clears itself as it goes down. rIhe side cutting flanges 14 do not of course register with the aforesaid annular flanges when the cutters are drawn out and the auger expanded, but they always clear the edgeof the hole.

l5 are screws threaded into suitable orifices in the under side vof the flanges 2 adj acent to the outside beveled edge of the channels 5 having their heads partly overlapping said channels and adapted to be tightened down and bind the outer edge of the cutters 8 securely. The flanges 2 are slightly dished toward the center, so that the outer edges are higher than the center. rlhis makes the outer ends of the cutter higher than the center, consequently the bottom of the hole being cut will be slightly cupped and any tendency for side play of the auger removed.

16 is the auger stem preferably formed of a length of pipe rigidly secured in the hub portion 3 by a suitable pin 1T and supporting a handle 1S at the upper end.

19 is the lead screw having a stem Q0 fixedly secured in the lower end of the stem 1G and extending' therebelow and having a central core formed with a double spiral flange 21 extending therearound. The double spiral flange is formed with its lower side undercut or beveled upwardly and inwardly so that it presents a cutting edge to the ground as the auger is turned. rlhe flanges 21 terminate at the point of the lead screw in a pair of cutting lips 22 projecting downwardly. lith this form of lead screw there is no resisting under surface and therefore no downward pressure is required to cause the auger to feed its way into the ground, as the cutting edges cut their way in, and the contact of the upper surface of the spirals draws downwardly thus pulling` the auger downwardly as it is rotated and forcing the cutters into the ground.

The construction shown in Figs. 2, 4 and G is very similar to that shown in Figs. 1, 3 and 5 the only difference beingl that the channels in the underside of the spirals extend only slightly past the center and the cutters are much shorter and slightly different in construction. The cutters are formed with beveled shoulders Sa and 8b on each side, said shoulders being' adapted to fit snugly against the beveled edges 7" and both ends of said cutters are curved similarly to 'correspond with the peripheral diameter of the spiral flanges.

14a are flanges corresponding with the flanges le arranged at each end of the said cutters, one flange extending upwardly and the other downwardly. As both faces of the cutters are similarly formed the screws 13 may be removed and the cutters turned over endwise, thus bringing the former inner end to the outside and the top side downward.

In using this device the lead screw is started into the ground and on being turned it draws downwardly forcing the cutters into the ground and holding them constantly to their work. As the earth is cut away, the auger may be withdrawn from the hole lifting the loosened earth to the surface. A considerable range in the size of holes to be bored may be had with this device for the cutters can be adjusted to cut a hole about twice the size of the spiral body portion.

In cases where a large hole is to be cut and the earth is too heavy to be handled, a small hole may be first cut and the cutters expanded to make a second cut. The lead screw is then useless, but the dished undersurface rests in the first hole cut and guides the auger in making the second cut.

The device is very simple and the cutters l l l may be sharpened from time to time and when worn out, may bc readily replaced.

ln this description l have described the auger as used for digging post holes, but it must be understood that it may be adapted for use in boring holes in ice or wood and further may be adapted for use as an ordinary brace bit without departing from the spirit of the invention so long as the salient features are adhered to.

That I claim as my invention is 1. In an auger, a body portion formed of spirally arranged flanges, and a pair of cut` ters adjustably secured to said flanges to each side of the center and parallelly arranged one to the other.

2. In an auger, a` body portion formed of spirally arranged flanges, said flanges havingv channels in the under sides arranged to each side of the central lead screw and in parallel relation one to the other, cutters slidably arranged in said guides and means for holding said cutters rigidly.

3. In an auger, a body portion formed of a pair of spirally arranged semi-circular flanges, said flanges having upwardly extending edges and dove-tailed grooves or channels formed in the under sides thereof to each side of the center and extending in pa 'allel relation one to the other, and cutters having beveled edges engaging the beveled edges of said dove-tailed grooves and sliding in said grooves and having the forward portions of their upper face forming the continuations of the upper spiral faces of the said flanges.

t. In an auger, a body portion formed of a pair of semi-circular spiral flanges having edge flanges projecting upwardly therefrom, cutters adjustably secured to said body portion and arranged in parallel relation one to the other to each side of the center and forming a continuation of the lower side of said spiral flanges, said cutters having flanged edge cutters extending in right angular relation from the face thereof and corresponding with the upwardly extending edge flanges on said body portion.

5. In an auger, a body portion formed of a pair of spirally arranged flanges having dove-tailed grooves formed in the undersides thereof, said flanges being cut away from the center at their lower edges and formed with an upwardly beveled face, cutters having beveled edge shoulders formed adjacent to the cutting edge and adapted to engage the beveled lower edge of said spiral flanges, and means for holding said cutters with their beveled faces engaging the beveled edge faces formed in said body portion.

G. ln an auger, a body portion formed of a pair of semi-circular spiral flanges, a suitable lead screw secured centrally in said body portion and extending downwardly therefrom, :t pair of cutters adjustably secounty of York, in the Province of Ontario, cured to the under side of said spiral anges in the Dominion of Canada this 16th clay of arranged to each side of said lead screw and J une 1908.

in parallel relation one t0 the other, and JOHN VILLIAM CALDVELL. 5 means for securing Said cutters in their ad- VVitnesseS:

justecl positions. H. DENNISON,

Signed at the city of Toronto in the WVM. C. MUIR. 

